Solenoid winding



P. TRoMBl-:TTA

April 1, 1930.

SOLENOID WINDING Inventor: Fanfdo Trombetta,

HLS Attorney.

Patented Apr. l, 1930 PANFILO TROMBETTA, OF SCHENECTADY, NEW YORK, ASSIGNOR. TO GENERAL ELECTRIC COMPANY, A CORPORATION F NEW YORK SOLENOID WIN DING Application led December 31, 1928. Serial No. 329,602.

My invention relates to solenoid windings. More particularly, it relates to the structure of the spool body for the winding, and has for its object the provision of an improved,

simple and inexpensive spool body that may be quickly and easily wound, and which makes possible the largest possible winding factor commensurate with the available winding space.

In the past, in order to avoid having the lead to thev inner layer lie along the inner surface of the iange and the uneven winding resulting therefrom, it has been customary either to pass the lead through a hole in the flange located near the surface of the winding body or to employ a spool provided with an intermediate flange and `wind the coil from the winding body of the spool, outwardly toward the circumference in each section.

The first of the two methods outlined above is unsatisfactory because when coils of this type are stacked the leads passing through the flanges lie between adjacent flanges of the stacked coils resulting in an uneven stack, and the second method is undesirable because the intermediate flange results in a coil having a poor winding factor. l

In carrying out my invention in one form I provide a groove or recess on the outside surface of the spool body through which the lead to the inside layer passes.

For a better and more complete understanding of the invention, reference should be had to the following specification and to the accompanying drawings in which Fig. 1 is a view partly in section of the spool body and of insulating elements used for properly insulating the leads from the layers of turns of the winding; Fig. 2 is a broken view in which the insulating elements of Fig. 1 are properly placed on the spool body and the spool body is shown as in readiness to be wound, the first turn being partially wound upon the spool; while Fig. 3,shows the completed solenoid with leads provided for connection to a source of electric power.

Referring now to the drawing, I have shown the invention as applied in a solenoid 5' winding, whichk though suited for` general use is for operating a brake. As shown, a

winding body comprising the central portion 10 of a cylindrical oblong shaped spool body is provided with end flanges 12 and 13 suitably dimensioned to' provide awinding space large enough to accommodate the desired number of turns. The spool body may be made of any suitable insulating material, butV I prefer to mould it from a'compound containing shredded cloth and a phenolic condensation product known to the trade as bakelite.

An end face of the winding body 10 and an inner surface of the fiange 13 are provided with a shallow L-shaped groove 14, one of the laterals of the L being located in the winding body 10 of the spool, and the other in the Harige 13 as shown in the drawing. It extends longitudinally the full length of the winding space between flanges 12 and 13 and radially from the winding surface 10 to the periphery of the flange 13, and its width is from one third to one half that of the end face of the winding body. It is not necessary that the groove 14 be provided in an end face of the winding surface. It may be located in a longitudinal face if desired. In the bottom surface of the groove 14 and centrally thereof, a second groove 15 is provided which, like groove 14, extends the full length of the winding space between 'the flanges 12 and 13 and radially from the winding body 10 to the periphery of the flange 13. This groove, as shown, is approximately one third the width of groove 14 and is of a depth that depends upon the size of the conductor with which the coil is to be wound.

In winding the solenoid, the procedure is as follows: The spool body is first secured to the mandrel of a suitable winding machine. A strip of suitable insulating material 16 preferably varnished cambric having substantially the same width as slot 14 and sufiiciently long to extend the length of the winding space and. the radial length of the fiange and back across the outside or top layer of the coil (see Fig. 3) is placed in slot 14. This is not indispensable, but is desirable for the purpose of preventing creepage. A

' piece of varnished canibric tubing 17 known terial such as a varnish ltreated paper are then placed in the groove 14, so as to cover lead 18 lying'in lower groove 15. These strips are of substantially the same dimensions as strip 16, and serve to house the lead 18 in the groove 15 and to insulate it from the layers of turns of the winding as is shown in Figs. 2 and 3. A lead spacer 2O made of a rather rigid insulating material such for example as horn fibre and provided with small notches 21 at either end to accommodate the conductor 18, is placed in the portion of the slot 14 located on the winding surface 10 and serves to space apart the free end of conductor 18 from the reel lead while the first layer of turns is being wound.

Before the actual winding operation be- `gins, split collars 22 and 23, preferably made of' a soft insulating material such as a varnish treated inuslin cloth, are placed upon the spool body so as to lie against the flanges 12 and 13, respectively. These collars are similar in shape to the flanges 12 and 13 but preferablyextend radially about a half inch beyond the periphery of the flanges.

The spool body is now ready to be wound,l

and this is done by rotating the spool bodyy on the mandrel of a winding machine untilthe desired number of turns have been applied.

After the solei` oid has been wound, the ini sulating strips 16 and 19 and the lead 18 are folded up over the outside layer of turns as shown in Fig. 3, after which the muslin collars 22 and 23 are folded over the outside layer and secured by any suitable fastener such as string or cord. A suitable` filler (not shown) such as a varnish treated cotton is then wound about the coil to fill upon the remaining winding space and to give a neat and finished appearance to the solenoid. The leads may be brought out as desired in accordance With standard practice.

Thus it will be seen that I have provided a solenoid that is easily and quickly wound, and in which the portions of the Winding subjected to the greatest difference in potential are properly insulated from each other.

Although I have illustrated and described the invention as embodied in concrete form as provided in the patent statutes, I do not intend lto limit myself to the precise form or dimensions shown, since modifications thereof will readily suggest themselves to those skilled in the art Without departing from the spirit or scope of the annexed claims.

What I claim as new and desire to secure by Letters Patent of the United States is: e

1. A spool for electrical coils comprising a winding body and a flange at each end thereof, one of said flanges being recessed on its inner side from said winding body to the outer edge of said flange to provide a passageway through which the conductor forming the coil extends to the inner layer of the coil whereby uniform winding is produced.

2. A spool for electrical coils comprising a body upon which the conductor forming said coil is wound in a plurality of layers, a flange on one end of saidbody, said body and said flange being provided with a passageway for the end of the conductor leading to the inner layer, said passageway extending from the other end of the coil to said flange end and thence to the exterior of the coil.`

3. An electrical winding comprising a spool having a winding body, a projecting flange at each end of said winding body, a coil wound in a plurality of layers upon said winding body, said body being provided with a recess extending throughout its length, and one of said flanges being provided with a recess extendinf1V fioin said first recess to the outer edge of the flange, said recesses providing a passageway through which the lead is passed from the inner surface of the other flange to said one` flange and thence to the exterior of the winding.

4. A spool for electrical coils comprising a body upon which the turns of the coil are wound in a plurality of layers, said body being provided with a recess extending throughout substantially the length of said coil, said recess providing a passageway beneath said coil through which the inner end of said conductor is led from one end of the body to the other and means for electrically insulating the portion of said conductor lying Within said passage way. I j

5. An electrical winding comprising a spool having a substantially V cylindrical winding body, an outwardly projecting flange at each end of said winding bo,dy,"'anelec trical conductor wound upon sidbodyljin' a plurality of layers, each' layer extending throughout substantially the length of said winding body, one of said flanges being provided witli a recess extending from the Winding body to the outer edge of said flange so that the inner end of said conductor passing portion being provided with a longitudinal recess in the outer surface thereof and one of said flanges being provided with a recess joining and extending from said first recess to the outer edge of said flange said recess providing a passage through which one end of said conductor is led to said inner layer and means for electrically insulating the portion of said conductor led through said passage way from the adjacent end of said coil.

spool having a winding body, a projecting 3o flange at each end of said body, a coil wound in a plurality of layersupon said winding body, said body being provided with a rccess extending throughout its length and one of said'anges being provided with a recess extending from said first recess to' the outer edge of the fiange, said recesses providing a 1 passageway through which the lead is passed from the inner surface of the other flange to 40 the winding, and a spacer member positioned in said first recess and extending between said flanges, said member serving to space the free end of the lead from the first turn of the coil.

In witness whereof, I have hereunto set my hand this 28th day of December, 1928.

PANFILO TROMBETTA. 

